High density ferrous power metal alloy
AssigneeKeystone Investment Corporation
InventorJohn C. Kosco
Life of this patent
Estimating the term…
Abstract
A method for producing high density and/or high surface density ferrous powder metal parts has the steps of: compacting a iron-containing powder substantially free of graphite at room temperature and at about 40-50 tsi; sintering the green compact in an inert, non-oxidizing environment at a temperature of about 2050.degree.-2300.degree. F.; repressing the sintered compact at room temperature at about 60 tsi; carburizing the repressed compact at high temperature to form a layer of relatively high carbon concentration to a depth of at least about 0.010 inches; and immediately quenching the hot carburized compact followed by a tempering treatment.
Claims48
A method for producing a sintered ferrous material having high density, high surface hardness and desirable rolling contact fatigue properties, the method comprising the steps of:
- compacting a portion of a powder at about 40 to about 50 tsi to provide a green compact, said powder comprising iron and iron alloys and being substantially free of graphite;
- heating said green compact in an inert, non-oxidizing environment at a temperature between about 2050.degree. F. to about 2300.degree. F. to provide a sintered compact;
- repressing said sintered compact at about 60 tsi to provide a repressed compact;
- carburizing said repressed compact in a controlled environment at high temperature to introduce carbon into said repressed compact to thereby provide said compact with a layer of relatively high carbon concentration to a depth of at least about 0.010 inches, said carburizing step thereby providing a heated carburized compact at a temperature greater than room temperature;
- quenching said heated carburized compact to bring the temperature of said carburized compact to about room temperature to provide a quenched compact;
- and
- tempering said quenched compact to provide a tempered compact.
The method of claim 22 wherein after said carburizing step said carburized compact has a density of about 7.50 to about 7.70 g/cc.
A method for producing a sintered ferrous material having high density, high surface hardness and desirable rolling contact fatigue properties, the method comprising the steps of:
- compacting a portion of a powder at about 40 to about 50 tsi to provide a green compact, said powder comprising iron and iron alloys and being substantially free of graphite;
- heating said green compact in an inert, non-oxidizing environment at a temperature between about 2050.degree. F. to about 2300.degree. F. to provide a sintered compact;
- extruding the sintered compact through a die to obtain a reduction in diameter of about 2% to about 6% to provide an extruded compact;
- carburizing said extruded compact at high temperature to introduce carbon into said extruded compact to thereby provide said compact with a layer of relatively high carbon concentration to a depth of at least about 0.010 inches, said carburizing step thereby providing a heated carburized compact at a temperature greater than room temperature;
- quenching said heated carburized compact to bring the temperature of said carburized compact to about room temperature to provide a quenched compact;
- and
- tempering said quenched compact to provide a tempered compact.
A method for producing a sintered ferrous material having high density, high surface hardness and desirable rolling contact fatigue properties, the method comprising the steps of:
- compacting a portion of a powder at room temperature at about 40 to about 50 tsi to provide a green compact, said powder comprising iron and iron alloys and being substantially free of graphite;
- heating said green compact in an inert, non-oxidizing environment at a temperature between about 2050.degree. F. to about 2300.degree. F. to provide a sintered compact;
- repressing said sintered compact at room temperature at about 60 tsi to provide a repressed compact;
- extruding said repressed compact through a die for a reduction in diameter of about 2% to about 6% to provide an extruded compact;
- carburizing said extruded compact at high temperature to introduce carbon into said extruded compact and thereby provide said compact with a layer of relatively high carbon concentration to a depth of at least about 0.010 inches, said carburizing step thereby providing a heated carburized compact at a temperature greater than room temperature;
- quenching said heated carburized compact to bring the temperature of said carburized compact to about room temperature to provide a quenched compact;
- and
- tempering said quenched compact to provide a tempered compact.
A method for producing a sintered ferrous material having high density, high surface hardness and desirable rolling contact fatigue properties, the method comprising the steps of:
- compacting a portion of a powder at about 40 to about 50 tsi to provide a green compact, said powder comprising iron and iron alloys and being substantially free of graphite;
- heating said green compact in an inert, non-oxidizing environment at a temperature between about 2050.degree. F. to about 2300.degree. F. to provide a sintered compact;
- extruding the sintered compact through a die to obtain a reduction in diameter of about 2% to about 6% to provide an extruded compact;
- repressing said sintered compact at room temperature at about 60 tsi to provide a repressed compact;
- carburizing said extruded compact at high temperature to introduce carbon into said extruded compact and thereby provide said compact with a layer of relatively high carbon concentration to a depth of at least about 0.010 inches, said carburizing step thereby providing a heated carburized compact at a temperature greater than room temperature;
- quenching said heated carburized compact to bring the temperature of said carburized compact to about room temperature to provide a quenched compact;
- and
- tempering said quenched compact to provide a tempered compact.
Dependencies are inferred from the claim text.